RestTemplate＆Jackson - 自定義JSON反序列化？

Question

webservice返回一個空字符串，而不是NULL，導致Jackson崩潰。 因此，我創建了一個自定義分析器，我試圖手動解析它？任何想法我怎麼能做到這一點？

我在這裏做錯了什麼？我想要做的就是像往常一樣將JSON解析爲對象。字段名稱使用@JsonProperty添加到我的屬性中，因此解析器應該知道如何轉換它。

public class InsertReplyDeserializer extends JsonDeserializer<ListingReply> { 

    @Override 
    public ListingReply deserialize(JsonParser jsonParser, DeserializationContext arg1) 
      throws IOException, JsonProcessingException { 

     ObjectCodec oc = jsonParser.getCodec(); 
     JsonNode node = oc.readTree(jsonParser); 

     // If service returns "" instead of null return a NULL object and don't try to parse 
     if (node.getValueAsText() == "") 
      return null; 


     ObjectMapper objectMapper = new ObjectMapper(); 
     ListingReply listingReply = objectMapper.readValue(node, ListingReply.class); 


     return listingReply; 
    } 

} 

Answer 1

這是我如何解決它

@Override 
public MyObject deserialize(JsonParser jsonParser, DeserializationContext arg1) 
     throws IOException, JsonProcessingException { 

    ObjectCodec oc = jsonParser.getCodec(); 
    JsonNode node = oc.readTree(jsonParser); 

    if (node.getValueAsText() == "") 
     return null; 

    MyObject myObject = new MyObject(); 
    myObject.setMyStirng(node.get("myString").getTextValue()); 

    JsonNode childNode = node.get("childObject"); 
    ObjectMapper objectMapper = new ObjectMapper(); 
    ChildObject childObject = objectMapper.readValue(childNode, 
      ChildObject.class); 

      myObject.setChildObject(childObject); 
      return myObject; 
} 

Answer 2

我不知道你需要手動解析響應。你的解決方案會工作，但在我看來似乎不是最佳。由於看起來您正在使用RestTemplate，因此您應該將自己的消息轉換器編寫（或將解析器代碼移至）。然後將此轉換器添加到您的休息模板對象中，該對象將爲您內部反序列化該值。東西沿線，

public class CustomHttpmsgConverter extends AbstractHttpMessageConverter<Object> { 
private ObjectMapper objectMapper = new ObjectMapper(); 
@Override 
protected Object readInternal(Class clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException { 
    InputStream istream = inputMessage.getBody(); 
    String responseString = IOUtils.toString(istream); 
    if(responseString.isEmpty()) //if your response is empty 
    return null; 
    JavaType javaType = getJavaType(clazz); 
    try { 
     return this.objectMapper.readValue(responseString, javaType); 
    } catch (Exception ex) { 
    throw new HttpMessageNotReadableException(responseString); 
    } 
} 

//add this converter to your resttemplate 
    RestTemplate template = new RestTemplate(); 
    List<HttpMessageConverter<?>> converters = new ArrayList<HttpMessageConverter<?>>(); 
    converters.add(new CustomHttpmsgConverter()); 
    template.setMessageConverters(converters);